Save the crank I say!!!! Thoughts?

[Rabbit79]

1984, 1.6 NA, JK engine code, in the midst of a re-build.
Well I took all my stuff in to the machine shop today to get all the machine work done, and they didn't want to have anything to do with my crank. The crank mics out within tolerances, but one of the rod journals was getting close so I thought I'd just go ahead and have them grind it so I'd have a nice clean crank when I put it all back together. Also in my original plan was to have them cut another slot for the woodruff key that holds the timing belt drive sprocket, and this is where we ran into differences. The original slot is wallowed out past helping, but I was thinking I could cut another slot 180 degrees out from the original, and it should work fine, since it doesn't really matter where it is on the crank, just that it doesn't rotate on the shaft. Am I off base here? He also said he thought the sprocket should be a press on fit. I do have to admit there is some axial play when you slide the sprocket on there but that goes away when you put the bolt and washer on hand tight. I don't recall seeing anything in the Bentley about that, and the Haynes doesn't say anything either (sorry I left my Bentley with them in case they wanted to use it for reference). If I have to get a new crank that's just how it goes sometimes and it's no big deal, although it would keep my costs down somewhat if I can save it, and I'm of the opinion that it can be saved. Thoughts? Comments? Opinions? All are welcome.
I'll try to get a picture in if I can figure it out.

[theman53]

save the crank. have it machined for one of the TDI sprokets like this. Done:D

[Rabbit79]

I'm not totally sure, but I don't think you can do that with this style of crank.

[Rabbit79]

I'll expand on that a bit, and this is just stuff I've gleaned from parts literature and reading on here, I'm certainly no aficianado on the subject so someone please correct me if I'm wrong. As I understand it, on cranks up to 82 the hub that the sprocket sits on was 22mm in diameter and the sprocket is held in place by a standard woodruff key. After 82 they enlarged the hub to 31mm and put a different locking mechanism on. I've never actually worked on one of the 31mm hubs so I don't know exactly how that works but from a few pictures I've seen it looks to be some sort of wedge shaped thing. I think to do the modification you're talking about I'd need to have a crank with a 31mm hub. Now according to the Bentley the JK codes start in 83 so I should have the bigger nose crank, but I don't. How the 22mm crank got in there is anyone's guess, but that's what I have so that's what I'm working with.

[Rabbit79]

Yes....Actual woodruff key.

[Rabbit79]

That's dis-heartening......Looks like I'm going shopping. Anyone know where I can find a crank?
Also that leads me to ask: Aren't the cranks for the 1.6 the same except for that hub the timing sprocket rides on? If so couldn't I upgrade to a new crank with a bigger hub and then do the TDI mod mentioned above?

[arb]

You could still have the woodruff slot cut anywhere on the crank, tho.  I should have said, you're SOL WRT using the TDI sprocket.

You could upgrade the crank and then use the TDI sprocket.

That's what I'd do - get the 31 mm crank and upgrade to the TDI sprocket...  my 1984 has the TDI sprocket :-)

[lord_verminaard]

Save it.  Here is another option:
http://www.vwdiesel.net/forum/index.php?topic=13828.0

Good luck-

Brendan

[Rabbit79]

I was pretty sure I could just cut another key slot in it and that would work.......... My other concern is the fit of the sprocket on the shaft. Should it be a press on fit on these early style sprockets? Mine definitely is not, it easily slides on and off by hand. There is some axial play when the sprocket is just on the shaft by itself. It almost seems as if that's by design though because the washer is shouldered and it fits tightly inside the sprocket and takes out all the play when you tighten it up. I just don't know for sure if that's how it's SUPPOSED to be. I don't see much in the books on this.


Brendan I looked at your thread on the dowel pins and I like the idea. It looks to be a little tougher proposition on the early style sprocket but I think it is workable. That raised shoulder around the bolt hole on the early style is only about 4mm thick, so if you wanted to stay inside of that you'd have to use a very small drill bit, or you'd have to bore out your jig so that it fits down over the shoulder and guides your drill bit all the way down til you hit the flat part.

[truckinwagen]

nope, not a press fit.

the early crank nose relies on the mechanical connection of the woodruff key, not the friction against the face of the crank.

as long as the pulley is not allowed to rotate any(with the key installed) you should be fine.

have them cut a new keyway and install a key that is wider than stock, as it will hold better than the narrow key originally there.

-Owen

[Rabbit79]

Well that news certainly makes my day a little brighter. I think if I can combine the new keyway with the dowel pin idea I'd have a pretty strong setup.  If all goes well we may have just saved a crank from becoming a paperweight.

[RabbitJockey]

i epoxied my keyway and installed a new gear.  has worked for over 2 years now.  it was either that or pull an engine that had 85k on it.  but if i were you, i'd ditch the early crank.  how ever i do agree with you that having the key 180 degrees off shouldn't make a difference assuming the gear has an even amount of teeth.  i don't know if you can even cut the early crank nose into a tdi D style.

[RadoTD]

I'm planning to pin my crank as well. Pinning should be stronger as the pin will be thicker than a bolt for the hole size due to no threads.

Probably do 3 extra pins, 90deg out from each other then the keyway. Also planning on putting on either red lock tite or some form of epoxy between the crank nose and the sprocket.

Between all of those, I figure it should hold.

[truckinwagen]

pic dont work

[Rabbit79]

Yes that's me trying to figure out how to do it.....think I'm getting there.